path: root/include/linux/mtd/mtd.h
diff options
authorBrian Norris <>2010-08-24 18:12:00 -0700
committerDavid Woodhouse <>2010-10-24 23:37:24 +0100
commitcc26c3cd3d1cf40a07f2b19ac4c53d517bee52a5 (patch)
tree664c422944f780a1cc99f872714eeb339efef7ef /include/linux/mtd/mtd.h
parentf4a2da0cd522a3b805ff2386c14912945bf990c7 (diff)
mtd: nand: expand nand_ecc_layout, deprecate ioctl ECCGETLAYOUT
struct nand_ecclayout is too small for many new chips; OOB regions can be as large as 448 bytes and may increase more in the future. Thus, copying that struct to user-space with the ECCGETLAYOUT ioctl is not a good idea; the ioctl would have to be updated every time there's a change to the current largest size. Instead, the old nand_ecclayout is renamed to nand_ecclayout_user and a new struct nand_ecclayout is created that can accomodate larger sizes and expand without affecting the user-space. struct nand_ecclayout can still be used in board drivers without modification -- at least for now. A new function is provided to convert from the new to the old in order to allow the deprecated ioctl to continue to work with truncated data. Perhaps the ioctl, the conversion process, and the struct nand_ecclayout_user can be removed altogether in the future. Note: There are comments in nand/davinci_nand.c::nand_davinci_probe() regarding this issue; this driver (and maybe others) can be updated to account for extra space. All kernel drivers can use the expanded nand_ecclayout as a drop-in replacement and ignore its benefits. Signed-off-by: Brian Norris <> Signed-off-by: Artem Bityutskiy <> Signed-off-by: David Woodhouse <>
Diffstat (limited to 'include/linux/mtd/mtd.h')
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 8485e42a9b09..03a1e954c586 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -110,6 +110,21 @@ struct mtd_oob_ops {
uint8_t *oobbuf;
+#define MTD_MAX_ECCPOS_ENTRIES_OLD 64 /* Previous maximum */
+ * Correct ECC layout control structure. This replaces old nand_ecclayout
+ * (mtd-abi.h) that is exported via ECCGETLAYOUT ioctl. It should be expandable
+ * in the future simply by the above macros.
+ */
+struct nand_ecclayout {
+ __u32 eccbytes;
+ __u32 oobavail;
+ struct nand_oobfree oobfree[MTD_MAX_OOBFREE_ENTRIES_LARGE];
struct mtd_info {
u_char type;
uint32_t flags;